土酸溶液中溴化十六烷基吡啶对锌的缓蚀作用及吸附热力学研究

用失重法研究了土酸溶液中溴化十六烷基吡啶对锌的缓蚀作用，发现溴化十六烷基吡啶在锌表面上的吸附是产生缓蚀作用的重要原因，且吸附规律服从Langmuir吸附等温式。用Sekine方法处理实验数据，从而获得了吸附过程△H^0、△S^0和△G^0等一系列重要热力学参数。     

The Use of Biopreservatives in the Control of Bacterial Contaminants of Sugarcane Alcohol Fermentation

ABSTRACT: Efficacy and safety of biopreservatives were studied for microbiological control of alcohol fermentation. Minimum inhibitory concentrations of nisin and lysozyme, and combinations with EDTA and Tween 20, were determined for Lactobacillus plantarum, L. fermentum , and L. confusus. The highest MIC value for nisin was 9.0 ppm for L. fermentum. Lysozyme was efficient against L. plantarum (700 ppm). A 2⁴ factorial design was used to study the effect of biopreservatives and potentiators on the growth kinetics of Lactobacillus fermentum. The combination of 8.6 ppm of nisin plus 0.1% of Tween 20 delayed the lag phase by 12 h. The biopreservatives did not affect the fermentation kinetics of Saccharomyces cerevisiae.     

钽铌水冶分解提取工艺及设备的进展

介绍了近些年来我国钽铌湿法冶炼中的资源结构，氢氟酸分解、矿浆萃取工艺以及工艺设备的进展情况。比较了主要工艺过程的技术经济指标，指出了当前生产中存在的一些问题，并提出了解决问题的一些意见。     

醋酸钾催化合成肉桂酸

对用醋酸钾作催化剂，以苯甲醛和醋酸酐为原料，通过Perkin反应制备肉桂酸进行了研究，经正交试验得出反应的最佳工艺条件：苯甲醛／醋酸酐摩尔比1：3，催化剂用量6g，反应时间2h，反应产率48．59％。     

合成直链烷基苯环境友好固体酸催化剂的研究 Ⅲ .催化剂失活原因分析

采用固定床反应器,对催化剂的稳定性进行了初步评价。在120℃、空速相同、液固反应条件下,高苯烯比时催化剂的稳定性明显高于低苯烯比时;在苯烯比和空速相同、液固反应条件下,相对低温反应时,催化剂的稳定性明显高于高温反应。IR分析结果表明,同新鲜和反应后未失活的催化剂相比,失活后催化剂的活性组分特征衍射峰消失,出现的新的特征衍射峰可能同—CH基的振动有关。TG分析结果表明,失活后催化剂在空气流中焙烧,失重幅度比新鲜催化剂大。     

固体酸的酸性和结构对苯与乙烯烷基化的影响

在搅拌高压釜中,研究了纯磷钨酸、负载磷钨酸、工业Y-分子筛、工业β-分子筛和纳米β-分子筛5种固体酸催化剂进行苯与乙烯的液相烷基化反应的催化活性和反应选择性。实验结果表明,固体酸催化剂的烷基化反应活性高低主要取决于表面酸强度和酸量;乙苯的选择性主要取决于催化剂的孔道结构;乙基化的选择性则与催化剂的表面酸强度、酸性中心位置和孔道结构等因素有关。     

Effect of organic dopants on electrodeposition and characteristics of polyaniline under the varying influence of H2SO4 and HClO4 electrolyte media

Electrodeposition of conducting polyaniline (Pani) was made under potentiostatic condition at pH 1.0 in different electrolyte media (H₂SO₄ and HClO₄) in the absence and presence of two organic dopants, disodium salts of naphthalene-1,5-disulphonic acid (NSA) and of catechol-3,5-disulphonic acid (CSA). The rate and yield of Pani deposition were dependent on the acid medium and the dopant employed. NSA in H₂SO₄ caused an increase in rate and yield but CSA decrease when compared to the rate and yield of H₂SO₄ alone. In HClO₄ medium, both the dopants showed a decrease. With regard to DC electrical conductivity, both the dopants exhibited an enhancement in H₂SO₄ medium but NSA a decline in HClO₄. Characterisation of the electrosynthesised polymer samples by various instrumental techniques (cyclic voltammetric: CV, FTIR, UV-Visible: UV-Vis, EPR, XRD, TGA and DTG methods) revealed that between the two acid media, H₂SO₄ was the better one. Further, it enlightened the role of two organic dopants in relation to the acid media. The advantageous role of NSA in H₂SO₄ had origin on its molecular characteristics such as non-polarity, larger π-electron cloud etc., while CSA could not perform such a role because of its easily oxidisable hydroxyl groups. In HClO₄, however, both the dopants could play only an unfavourable role owing to its greater polarity and oxidizing power than H₂SO₄.     

用磷铝杂原子固体酸催化剂合成马来酸二丁酯

以自制的磷铝杂原子固体酸催化剂催化合成了马来酸二丁酯，考察了反应时间、醇酸摩尔比、带水剂用量、催化剂用量等对酯化率的影响；同时考察了催化剂的重复使用性。对酯化产物物理性能进行了测试，其实测值与文献值相符。     

Sol-gel Preparation and Preliminary in vitro Evaluation of Fluorapatite／Hydroxyapatite Solid Solution Films

Fluorapatite/hydroxyapatite solid solution has better biological properties than other apatites, especially used as films or coatings. In this work, sol-gel preparation and in vitro behavior of fluorapatite/hydroxyapatite solid solution films on titanium alloy were investigated. Ca(NO3)2-4H20 and PO(OH)x(OEt)3-x were selected as precursors, and hexafluorophosphoric acid (HPFo) was used as a fluorine containing reagent. The Ca and P precursors were mixed with HPFo to keep the Ca/P molar ratio 1.67. The mixtures refluxed for 12 h were used as dipping sols for the preparation of the films. The phase of the films obtained at 600℃ was apatite. The F contents in the films increased with the concentrations of HPF6 in the dipping sols. The solid solution films were shown to have better stability than hydroxyapatite films, and a reasonably good bioactivity in the in vitro evaluation.     

Corrosion of tin in citric acid solution and the effect of some inorganic anions

The corrosion behaviour of tin in different concentrations of citric acid solutions (0.3–1.0 M, pH=1.8) was studied at 30 °C by potentiodynamic technique. The E/I profiles exhibit an active passive behaviour. The active dissolution involves one anodic peak A associated with a dissolution of the metals as Sn(II) species. The passivity is due to the formation of thin film of SnO₂ and or Sn(OH)₄ on the anode surface. The cathodic sweep shows a small peak C related to the reduction of the passive film. The peak current density I_p of peak A increases with increasing both acid concentration and sweep rate.

The effects of adding increasing concentrations of Na₂CrO₄, NaMoO₄, NaNO₃ and NaNO₂ on the corrosion of tin in 0.5 M citric acid at 30 °C were investigated. Both CrO₄²⁻ and MoO₄²⁻ ions inhibit the corrosion of tin and the extent of inhibition enhances with their concentrations. Addition of either NO₃⁻ or NO₂⁻ accelerates the corrosion of tin. NO₃⁻ ions are more aggressive than NO₂⁻ ions.